Telephone transmitter



Dec. 15 1925. 1,565,581

C. R. MOORE TELEPHONE TRANSMITTER Filed Oct. 5, 1921 l of this invention there is Patented Dec. 1,55, 1925. UNITED' STATES- PATENT OFFICE.

CHARLES RUBY' MOORE, OF MAPLEIIOOD,` NEW JERSEY, vSVBIGNOR T OMWESTEBN ELEC- TRIO COMPANY, INCORPORATED, OIF NEW YORK, N. Y., A. GORPORATIONv OP' NEW YORK.

TELEPHONE 'raansmrzn appu'aon mea october s`, 19,21.v serial No. 505,000.

To'aZZ whom t may concern.' v

Be it known that I, CHARLES RUBY MOORE, a citizen of the United States, resid-in at Maplewood, in the county of Essex, tate of New Jersey,.have.invented certain new and `useful Improvements in' Telephone Transmitters, of which the'follow-ing is a full, clear, concise,-and exact description.

This invention relates to telephone trans,

mitters and particularly to transmitters employing commnuted material as the current varying medium.

The object of theinvention in general is to provide a highly eiiicient and economical transmitter having a high resistance path through a commnuted material, whereby the transmitter may be operated directly across a voltage of a commercial telephone circuit. l

In accordance with thegeneral features rovided a construction in which the marginal walls of the carbon containing chamber form electrodes and a barrier located between the electrodes 'and extending transverse of the chamber in-' sulates them from each other except through the conducting path formed by the comminuted materlal, thereby providing a comparatively long ath for the assage of current between adjacent electro es. In its referred form the chamber for the comminuted material is cylindrical and suiiicient commnuted material is provided therein so that regardless of the osition 1n which the transmitter may be he d, the-,cir-V cuit through the commnuted material cannot be opened. In the drawing, Fig. 1 is' a sectional elevation of a transmitter embodying the invention. Fig. 2 is an exploded view parts of the transmitter, disclosed in 1*. Figs. 3 and 4 illust v"te applicat-ions o the invention to an inertia type transmitter and a repeater respectively.

In Fig. 1 casin 1 serves to inclose the working parts of t e transmitter and to support a face plate 2 which in turn' carries a mouth-piece 3. A diaphragm4 is supported against the face plate, and a bridge member 5 also carried b the faceplate serves to support the granu ar containing chamber 6.A

In. Figs'. 1 and 2 the granular containing chamber is of circular cup-like form. Annular electrodes 7 and 8 of brass or other suitable `'couducting material are mounted on the marginal walls of the chamber and insulated therefrom. SeparatingO the electrodes is a washer shaped barrier 9 of insulating, material having 'a lcentral opening through whichthe lcurrent between theelectrodes must pass. In the back of the chamber and insulated therefrom is a late 10 /to whichva rod 11' forming one e ectrode terminal is attached. The face of this plate is coated with insulating. material -except` near the edge where it, makes contact with the electrode 7. Securing the electrodes and the barrier in place is a clamping ring 12 threaded tothe cup 6. A flexible cover, dialragm 14,is secured by a similar ring 13.

upported in the center of the closure is a plunger 15 which is provided with a stud 1 by means of which vibrations ofthe main dlaphragm 4 are transmitted to the dia- 14. The-'plunger is held against the laphra 4 by a spring 17.

It is 'evi ent that the co-axial arrangement ofa'pair of jannular electrodes form- `ing the marginal wall of the carbon chamber and separatedfby an insulatingy ring, as shown in the drawings, rovid'es a trans.

.mitterin which friction tween 'the electrodes andthe carbon particles is minimized. In Figi?, the transmitter button is supported entirely by a diaphragm 18 to which it is attached'by means of a stud'- 21 connected to afplunger 20,'and a nut 19. ,To

. reduce the sensitivity of the device to vibrationsr other than'those in the direction of the movement of diaphragml 18, that fpartV v'of the button forming the electrode contain- Aing chamber` 25. is balanced by the member -26 attached to the outer wall 22 of the chamber and vextendingon the opposite side of showinl the the su porting dlaphragms 23 4and 24.

In ig. `4 t ebarrier 27 is integral with electrode 28 and rear wall 29 is integral with electrode 30. All parts except the marginal srface of the electrodes where contact with t e late l lThe two' most serious defects in transmitters of the granular carbon ty are their susceptibility to burning an packing.

(granular material is desired are insurent.

V this point remains substantially f constarnt in systems employing comparatively high voltages, for example 48 volt common battery systems or those in which a considerable power must. be transmitted. The principal cause of burning is the heat generated by the comparatively high voltage caused by the high resistance contactsl developed between the electrodes and the carbon granules due ton their tendency to separate when agitated. Packing is due to the heating action of the current and the crowding together of the ganules. In the former types of transmitters this resulted in the lower layers of the carbon mass, where the agitation is the least, carrying most of thecur- Transmitters embodying the features of the structure herein described eliminate direct action between the carbon granules and the electrodes. Therefore, the resistance at and any tendency which lthere may be toward packing will not shunt the current from the path of maximum agitation. By lengthening the path through the comminuted material, minimizing relative movement between the electrodes and the granules thereby minimizing friction and diirecting the current through the area of maximum agitation, a transmitter button is produced whose resistance is relatively high in comparison with transmitters heretofore known.

In the illustrations used for the purpose of describing the invention only two electrodes have been shown. It is obvious, however, that three or more electrodes similarly disposed with barriers between adjacent electrodes may-be used.

What is claimed is:

1. A transmitter comprising an electrode chamber, a pair of annular electrodes disposed in the mar inal wall of said chamber, and an annular insulating barrier between said electrodes of said chamber.

annularinsu ating barrier between Said electrodes, the inside diameter of said barrier being smaller than the inside diameter of either electrode.

3. A transmitter comprising an electrode` chamber, an annular partition dividing the chamber into twoparts, an annular electrode forming v,the marginal wall of each part, and "comminuted material forming a conducting` path between said electrodes throu h an opening in said partition.

4. E transmitter comprising an electrode chamber, a pair of annular electrodes disosed in the mar 'nal wall of said chamer, a partition dividing the chamber into two parts and insulating the electrodes from each other, comminuted conducting material projecting into the interioin connecting said electrodes, and means having movement parallel to theV faces of the velectrodes for agitating the comminuted matrodesV co-aXia-lly disposed therein, comminuted material connecting said electrodes, and a barrier for concentrating the current flow through said material at the center of the chamber. l 4

6. A telephone transmitter comprising an electrode chamber, a pair of annular electrodes co-axially disposed therein, comminuted material connecting said electrodes, and means for concentrating the current flow through said material at the center of the chamber, said means comprising an annular insulating member having an open therethrough. y

7. A telephone transmitter comprisin an electrode chamber, a plurality of co-axially disposed annular electrodes forming the marginal wall of said chamber, current coni ductlng material connecting said electrodes, means for agitating said material, and a barrier covering the adjacent plane surfaces o f said electrodes for concentrating the current through said material at the central are of maximum agitation in said chamber. 8. A telephone transmitter comprising an electrode chamber, annular electrodes dis'- posed in the Wall of said chamber, a iexible closure for said chamber, comminuted material agitated thereby, and an insulation washer between said electrodes for concentrating the current low at the area of maximum agitation. 9. A transmitter comprising a'chamber, a plurality ofannular electrodes forming the marginal wall of said chamber, a perforatedinsulating barrier transverse of said chamber between adjacent electrodes, and comminuted material connecting said electrodes through the perforation in said barrier, the ohmic resistance of the path through said comminuted material being comparatively high.

10. A telephone transmitter comprising an electrode chamber, electrodes rigidly mountedv therein to form the side walls of the chamber, means for insulating said electrodes from each other, granularA material connecting said electrodes, a plunger for a variable resistance medium between said electrodes, the electrodes being so mounted with respect to the active parts of the diaphragm that friction between the granules 5 and the electrodes is minimized..

12. A transmitter comprising an electrode chambeija plurality ofco-,axlally disposedv annular electrodes disposed inthe side walls of said chamber, conducting material in said chamber, connecting said electrodes, and a.A l0 perforated insulating member within said chamber between said electrodes.

In witness whereof, I hereunto subscribe` my name this 29th day of September, A. D.

l1921. CHARLES R. MOORE. 

